On 07/30/2017 11:28 AM, Tony Duell wrote:
On Sun, Jul 30, 2017 at 5:18 PM, Jules Richardson via cctalk
<cctalk@classiccmp.org> wrote:
On 07/30/2017 10:59 AM, Ian Frost via cctalk wrote:
Any body any experience in fixing these old Acorn PSUs - or managed to
source alternative modern supplies?
In general smoke from a power supply that keeps on working is from the
mains filter capacitors. Some makes are well-known for this. I would
carefully examine them, they crack when they fail
Aha, I missed the "kept working" bit... agreed there, then, it's probably
one of the input caps which failed (and that seems consistent with brown
goo on the PCB, too).
The former are the ones that normally fail, but I would change the lot.
I'd be inclined to agree in the case of any class X/Y caps as they're a
known failure point in any piece of vintage equipment... but not every
single cap in the PSU. I know that's not what you're suggesting, but there
seems to be a trend amongst collectors to blindly replace every cap in
sight as part of some "refurbishment process" these days, whether they're
good or bad. Personally I like to keep my systems as original as possible,
which generally precludes replacing perfectly-good vintage components with
perfectly-good modern ones :-)
I certainly traced out the schematics of mine, but I forget which PSU was
fitted to my machine (something tells me it was made by Farnell).
That could well be - I do think that I've seen another type of PSU used in
addition to the VMS one, and Farnell would be an obvious choice.
cheers
Jules
